hitl-mcp: Skill for Claude Code

Git Squash

Squash the current PR branch into one commit based on net branch changes relative to the default branch. Do not create or invoke a helper script. Run the Git commands directly.

Arguments

Parse $ARGUMENTS for optional flags:

• --subject <line>: Override the generated commit subject line
• --base <branch>: Override default-branch auto-detection

Defaults:

• Subject: infer a conventional-commit subject from the squashed changes themselves; do not default to chore
• Base detection order:
  1. refs/remotes/origin/HEAD
  2. git remote show origin
  3. main, master, trunk

Workflow

1) Pre-flight

Start by confirming that history can be rewritten safely. Stop on the first failure.

• Verify inside a Git worktree: git rev-parse --is-inside-work-tree
• Verify not detached: git symbolic-ref --quiet --short HEAD
• Verify working tree is clean: git status --porcelain
• After base detection, stop if the current branch is the default branch

git rev-parse --is-inside-work-tree
git symbolic-ref --quiet --short HEAD
git status --porcelain

2) Resolve the Base Branch

If --base was provided, use that branch name directly. Otherwise, detect the default branch in this order:

1. refs/remotes/origin/HEAD
2. git remote show origin
3. main, master, trunk

After the branch name is resolved, normalize it to a usable ref by preferring the local branch and falling back to origin/<branch>. Stop if neither exists. Also stop if the current branch is the default branch, because the skill should never squash the default branch into itself.

git symbolic-ref --quiet --short refs/remotes/origin/HEAD
git remote show origin
git show-ref --verify --quiet "refs/heads/$default_branch"
git show-ref --verify --quiet "refs/remotes/origin/$default_branch"

3) Find the Squash Boundary

Compute the merge-base between HEAD and the resolved default ref. That merge-base is the point where the branch diverged. Count how many commits are ahead of it. If the count is zero, there is nothing to squash.